Traditionally, many temporary construction work zone or traffic control signs are made of ⅝ inch to ¾ inch (16 to 19 millimeter) plywood. With such a material, the traditional method of changing a message is with an overlay, which changes at least a portion of the message, is to simply nail another piece of plywood over the original message and bend the nails over on the back side of the sign. This added piece of plywood nailed to the surface of the original sign creates several problems. First, it is difficult to remove the overlay when the overlay is not needed. Since the overlay is not easily removed, it stays with the sign when not in use. The extra thickness of the overlay creates difficulty when trying to stack many signs together. Furthermore, when several signs are stacked against each other, the bent over nails on the back of the sign with the overlay, destroys the costly retroreflective film on the face of the sign behind it.